Question
Solve the following simultaneous equation.
x + 7y = 10; 3x – 2y = 7
x + 7y = 10; 3x – 2y = 7
✓
Answer
$x+7 y=10 \ldots \text { (I) }$
$3 x-2 y=7 \ldots( II )$
Multiply Eq. I by 2 and Eq. II by 7
$2 x+14 y=20$
$\underline{21 x-14 y=49}$
$23 x=69 $
$x=\frac{69}{23} $
$x=3$
Substituting $x=3$ in Eq. 1
$3+7 y=10$
$7 y=10-3$
$7y=7$
$y= \frac{7}{7}$
$y=1$
∴ Solution is (x , y) = (3, 1)
$3 x-2 y=7 \ldots( II )$
Multiply Eq. I by 2 and Eq. II by 7
$2 x+14 y=20$
$\underline{21 x-14 y=49}$
$23 x=69 $
$x=\frac{69}{23} $
$x=3$
Substituting $x=3$ in Eq. 1
$3+7 y=10$
$7 y=10-3$
$7y=7$
$y= \frac{7}{7}$
$y=1$
∴ Solution is (x , y) = (3, 1)
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